Chin, Kuen Foo;
(2024)
The clinical and biomechanical study of the total elbow arthroplasty with emphasis on the humeral component.
Doctoral thesis (Doc.Orth), UCL (University College London).
Abstract
The total elbow arthroplasty had evolved since its first implantation in 1950’s. Lessons had been learnt from failure of historic implants including over-constrained articulation, suboptimal bearing surface, inadequate intramedullary osteointegration and infections. The elbow joint is not a simple ginglymoid joint as shown by articular contact pressure studies during range of motion and kinematic tracking studies. The differential AP and transverse diameter of the capitellum and the angulation of trochlear spool makes the forearm changes its plane as it flexes and extends. The kinematics of the elbow is still not fully reproducible with current elbow arthroplasty joint bearing design. The joint reaction force of the elbow has not yet been studied in vivo. Currently available elbow arthroplasty systems were designed based on joint kinetic data derived from various mathematical models which were prone to oversimplification. The calculated joint reaction force data showed that the ulno-trochlear joint reaction force could increase up to 9 times in the absence of a radial head whilst most current elbow arthroplasty clinical practice only involved replacing the ulnotrochlear joint. The clinical series of the Discovery Elbow replacement studied this thesis had a survival rate of 97% at 3 years and 90% at 5 years. Humeral component mal-alignment and poor ulna component cementation were weak predicting factors for failure. Although aseptic loosening is still the biggest reason for failure of elbow arthroplasty, the multifactorial nature of the failing elbow replacement should be approached with careful appreciation of the patient, their environment and functional goals and a methodical approach to the structural assessment. The finite element study and the laboratory study in this thesis provided data to explain the clinical findings of condylar bone resorption, bone remodelling around the anterior flange and loosening at the tip of the stem. The data also suggested design features which will be beneficial for improving strain profile on the stem and adjacent endosteal bone to reduce the rate of aseptic loosening. In summary, this thesis recommended a humeral stem with length of 100mm and should incorporate an internal condylar flange and an anterior flange with full contact to the humeral cortex. The data from the study also set out a foundation for accurate sampling of data for future in vivo study with instrumented implant and telemetry.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Doc.Orth |
| Title: | The clinical and biomechanical study of the total elbow arthroplasty with emphasis on the humeral component |
| Language: | English |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Surgery and Interventional Sci |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10193256 |
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